The "extends": "eslint:recommended" property in a configuration file enables this rule.

JavaScript environments contain a number of built-in global variables, such as window in browsers and process in Node.js. In almost all cases, you don’t want to assign a value to these global variables as doing so could result in losing access to important functionality. For example, you probably don’t want to do this in browser code:

window={};

While examples such as window are obvious, there are often hundreds of built-in global objects provided by JavaScript environments. It can be hard to know if you’re assigning to a global variable or not.